1,720,954 research outputs found
Dynamic Ray Allocation for Aliasing Mitigation in DDGI through Importance Sampling : MS-DDGI: Multisampling Dynamic Diffuse Global Illumination
No full textBackground. Modern video games rely on advanced rendering techniques to simulate realistic lighting. Probe-based global illumination systems relying on ray tracing like DDGI, a modern and dynamic approach introduced by Z. Majercik et al., can suffer from aliasing artifacts, particularly in scenes with small, bright emissive light sources. These artifacts arise from inconsistent and insufficient sampling of the environment around probes, leading to jarring visual patterns that degrade image quality and artistic flexibility. Objectives. This thesis aims to address the aliasing artifacts in DDGI by developing a novel technique called Multisampling Dynamic Diffuse Global Illumination (MS-DDGI). The primary goals are to investigate existing methods for artifact mitigation, design a dynamic importance sampling strategy for ray allocation, and evaluate the proposed solution's effectiveness in terms of visual quality, performance, and robustness. Methods. The research combines a literature review of Monte Carlo importance sampling and related rendering techniques with the implementation of MS-DDGI in the proprietary Snowdrop engine. The proposed system dynamically redistributes probe rays based on light importance, using probability density functions (PDFs) and cumulative distribution functions (CDFs) to prioritize high-impact directions. The evaluation includes qualitative visual comparisons, quantitative error analysis against reference renders, and performance profiling. Results. MS-DDGI significantly reduces aliasing artifacts, producing smoother and more consistent lighting in scenes with small emissive sources. Quantitative tests demonstrate lower mean squared error (MSE) compared to baseline DDGI, and domain experts confirm its visual improvements. However, the technique introduces a modest performance overhead in frame time and memory usage, with temporal delay as a notable trade-off. Conclusions. The study confirms that importance sampling can mitigate aliasing artifacts effectively for DDGI, enhancing visual fidelity and artistic usability. While the implementation incurs performance costs, the benefits justify its application in real-time rendering pipelines. Future work could optimize performance further and address temporal responsiveness.Bakgrund. Moderna spel förlitar sig på avancerade renderingstekniker för att simulera realistisk belysning. System för global ljussättning som förlitar sig på strålspårning som DDGI, en modern och dynamisk teknik introducerad av Z. Majercik et al., kan lida av aliasingartefakter, särskilt i scener med små, kraftfulla emissiva ljuskällor. Dessa artefakter uppstår på grund av ojämn och otillräcklig sampling av data i omgivningen, vilket leder till oönskade visuella mönster som försämrar visuell kvalitet och begränsar konstnärlig flexibilitet. Syfte. Detta examensarbete syftar till att åtgärda aliasingartefakterna i DDGI genom utvecklingen av en ny teknik: Multisampling Dynamic Diffuse Global Illumination (MS-DDGI). De primära målen är att undersöka befintliga metoder i bruk för att åtgärda liknande artefakter, bygga en ny, mer dynamisk samplingsstrategi för strålspårning, samt utvärdera den nya lösningens effektivitet i mån av visuell kvalitet, prestanda, och stabilitet. Metod. Forskningen kombinerar en litteraturöversikt kring relaterade renderingstekniker samt Monte Carlo importance sampling med implementationen av MS-DDGI i den företagsägda Snowdrop-motorn. Våran teknik omfördelar strålresurser dynamiskt baserat på existerande ljusfördelning, med hjälp av sannolikhetstäthetsfunktioner (PDF) och kumulativa distributionsfunktioner (CDF) för att prioritera riktningar med större påverkan. Utvärderingen omfattar kvalitativa visuella jämförelser, kvantitativ felanalys mot referensrenderingar, och prestandamätningar. Resultat. MS-DDGI minskar avsevärt inverkan av aliasingartefakter, vilket ger jämnare och mer konsekvent belysning i scener med små emissiva ljuskällor. Kvantitativa tester visar lägre medelkvadratfel (MSE) jämfört med tidigare teknik, och domänexperter understryker de visuella förbättringarna. Tekniken medför dock en mätbar prestandakostnad i mån om beräkningstid och minnesanvändning, tillsammans med märkbar tidsmässig tröghet. Slutsatser. Studien bekräftar att importance sampling kan tillämpas för att åtgärda aliasingartefakter effektivt för DDGI, vilket förbättrar det visuella resultatet och breddar den konstnärliga användbarheten. Implementationen medför prestandakostnader, men fördelarna understryker samtidigt starkt dess användbarhet för modern grafik. Framtida arbete kan innefatta optimering av prestandan ytterligare, och åtgärder för tidsmässig responsivitet
Dynamic Ray Allocation for Aliasing Mitigation in DDGI through Importance Sampling : MS-DDGI: Multisampling Dynamic Diffuse Global Illumination
No full textBackground. Modern video games rely on advanced rendering techniques to simulate realistic lighting. Probe-based global illumination systems relying on ray tracing like DDGI, a modern and dynamic approach introduced by Z. Majercik et al., can suffer from aliasing artifacts, particularly in scenes with small, bright emissive light sources. These artifacts arise from inconsistent and insufficient sampling of the environment around probes, leading to jarring visual patterns that degrade image quality and artistic flexibility. Objectives. This thesis aims to address the aliasing artifacts in DDGI by developing a novel technique called Multisampling Dynamic Diffuse Global Illumination (MS-DDGI). The primary goals are to investigate existing methods for artifact mitigation, design a dynamic importance sampling strategy for ray allocation, and evaluate the proposed solution's effectiveness in terms of visual quality, performance, and robustness. Methods. The research combines a literature review of Monte Carlo importance sampling and related rendering techniques with the implementation of MS-DDGI in the proprietary Snowdrop engine. The proposed system dynamically redistributes probe rays based on light importance, using probability density functions (PDFs) and cumulative distribution functions (CDFs) to prioritize high-impact directions. The evaluation includes qualitative visual comparisons, quantitative error analysis against reference renders, and performance profiling. Results. MS-DDGI significantly reduces aliasing artifacts, producing smoother and more consistent lighting in scenes with small emissive sources. Quantitative tests demonstrate lower mean squared error (MSE) compared to baseline DDGI, and domain experts confirm its visual improvements. However, the technique introduces a modest performance overhead in frame time and memory usage, with temporal delay as a notable trade-off. Conclusions. The study confirms that importance sampling can mitigate aliasing artifacts effectively for DDGI, enhancing visual fidelity and artistic usability. While the implementation incurs performance costs, the benefits justify its application in real-time rendering pipelines. Future work could optimize performance further and address temporal responsiveness.Bakgrund. Moderna spel förlitar sig på avancerade renderingstekniker för att simulera realistisk belysning. System för global ljussättning som förlitar sig på strålspårning som DDGI, en modern och dynamisk teknik introducerad av Z. Majercik et al., kan lida av aliasingartefakter, särskilt i scener med små, kraftfulla emissiva ljuskällor. Dessa artefakter uppstår på grund av ojämn och otillräcklig sampling av data i omgivningen, vilket leder till oönskade visuella mönster som försämrar visuell kvalitet och begränsar konstnärlig flexibilitet. Syfte. Detta examensarbete syftar till att åtgärda aliasingartefakterna i DDGI genom utvecklingen av en ny teknik: Multisampling Dynamic Diffuse Global Illumination (MS-DDGI). De primära målen är att undersöka befintliga metoder i bruk för att åtgärda liknande artefakter, bygga en ny, mer dynamisk samplingsstrategi för strålspårning, samt utvärdera den nya lösningens effektivitet i mån av visuell kvalitet, prestanda, och stabilitet. Metod. Forskningen kombinerar en litteraturöversikt kring relaterade renderingstekniker samt Monte Carlo importance sampling med implementationen av MS-DDGI i den företagsägda Snowdrop-motorn. Våran teknik omfördelar strålresurser dynamiskt baserat på existerande ljusfördelning, med hjälp av sannolikhetstäthetsfunktioner (PDF) och kumulativa distributionsfunktioner (CDF) för att prioritera riktningar med större påverkan. Utvärderingen omfattar kvalitativa visuella jämförelser, kvantitativ felanalys mot referensrenderingar, och prestandamätningar. Resultat. MS-DDGI minskar avsevärt inverkan av aliasingartefakter, vilket ger jämnare och mer konsekvent belysning i scener med små emissiva ljuskällor. Kvantitativa tester visar lägre medelkvadratfel (MSE) jämfört med tidigare teknik, och domänexperter understryker de visuella förbättringarna. Tekniken medför dock en mätbar prestandakostnad i mån om beräkningstid och minnesanvändning, tillsammans med märkbar tidsmässig tröghet. Slutsatser. Studien bekräftar att importance sampling kan tillämpas för att åtgärda aliasingartefakter effektivt för DDGI, vilket förbättrar det visuella resultatet och breddar den konstnärliga användbarheten. Implementationen medför prestandakostnader, men fördelarna understryker samtidigt starkt dess användbarhet för modern grafik. Framtida arbete kan innefatta optimering av prestandan ytterligare, och åtgärder för tidsmässig responsivitet
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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